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Microbiology for MCEM

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Food poisoning is a notifiable disease TRUE ... Food poisoning - Incubation periods. Staph. aureus 1-6 hours. E coli 1-2 days. Shigella 1-3 days ... – PowerPoint PPT presentation

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Title: Microbiology for MCEM


1
Microbiology for MCEM
2
Tetanus MCQ
  • A. The incubation period is usually in excess of
    28 days
  • B. Once the toxin is fixed to neurones,
    antitoxin is ineffective
  • C. The mortality of established tetanus depends
    upon previous immunisation
  • D. Patients with generalised tetanus present
    with trismus in 75

3
Tetanus MCQ
  • A. The incubation period is usually in excess of
    28 days FALSE
  • Usually 4 - 14 days, median 7 days
  • B. Once the toxin is fixed to neurones,
    antitoxin is ineffective TRUE
  • Recovery depends on sprouting new terminals and
    synapses
  • C. The mortality of established tetanus depends
    upon previous immunisation TRUE
  • 6 with 1-2 doses of vaccine, 15 without any
  • D. Patients with generalised tetanus present
    with trismus in 75 of cases TRUE
  • Other presenting complaints include stiffness,
    neck rigidity, dysphagia, restlessness, and
    reflex spasms

4
Tetanus MCQ
  • A. The current recommendations for immunisation
    provide 6 doses by the age of 18
  • B. There is a small risk of immunisation causing
    a mild form of tetanus
  • C. Tetanus vaccine given at the time of a
    tetanus-prone injury may not boost immunity
    early enough to give additional protection
    within the incubation period of tetanus
  • D. Tetanus prone wounds mandate the
    administration of immunoglobulin

5
Tetanus MCQ
  • A. The current recommendations for immunisation
    provide 6 doses by the age of 18 FALSE
  • Doses at 2,3,4 months, 3-5 years and 13-18 years
  • B. There is a small risk of immunisation causing
    a mild form of tetanus FALSE
  • The vaccines are inactivated, do not contain live
    organisms and cannot cause the diseases against
    which they protect.
  • C. Tetanus vaccine given at the time of a
    tetanus-prone injury may not boost immunity
    early enough to give additional protection
    within the incubation period of tetanus TRUE
  • D. Tetanus prone wounds mandate the
    administration of immunoglobulin FALSE
  • Only if wound is high risk as long as patient
    fully immunised

6
Tetanus
  • Clostidium Tetani is an obligate anaerobic gram
    positive bacillus
  • Spore forming resistant to heat, desiccation
    and disinfectants. Viable for years
  • Found in soil, animal intestines and human faeces

7
Tetanus
  • Tetanospasmin is released under anaerobic
    conditions, enters the nervous system
    peripherally at the myoneural junction and is
    transported centrally to neurons of the CNS.
  • Inhibits neurotransmitter release (mainly GABA -
    inhibitory). Shorter nerves affected faster
    therefore facial/back stiffness first.

8
Tetanus prone wound is
  • Wounds or burn sustained gt6 hours before surgical
    treatment.
  • Any wound or burn with
  • A significant degree of devitalised tissue.
  • Puncture wounds.
  • Wounds having come in contact with soil or manure
    likely to harbour tetanus organisms.
  • Clinical evidence of sepsis or compound fractures.

9
Tetanus
  • High risk wound should always be treated with
    immunoglobulin
  • Wound contaminated with horse manure / farmyard
  • The preventative dose of human tetanus
    immunoglobulin is
  • 250iu im in most cases,
  • 500iu im if
  • More than 24 hours have elapsed.
  • Risk of heavy contamination.
  • Burns.

10
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11
Immunisation
  • Once five doses of vaccine have been received at
    appropriate intervals, another dose of vaccine is
    not required following any type of wound.

12
Gastroenteritis MCQ
  • A. Gastroenteritis is bacterial in origin in
    15-20 of cases
  • B. Rotavirus is the leading cause of
    gastroenteritis in children
  • C. Food poisoning is a notifiable disease
  • D. Stool microscopy and culture is usually
    required

13
Gastroenteritis MCQ
  • A. Gastroenteritis is bacterial in 15 - 20 of
    cases TRUE
  • Common organisms include Shigella, Salmonella, C
    jejuni Yersinia enterocolitica, E coli
  • B. Rotavirus is the leading cause of
    gastroenteritis in children TRUE
  • Viruses cause 50-70 of all cases of
    gastroenteritis in the UK. Other viruses include
    Norwalk, Caliciviruses, Adenovirus and Parvovirus

14
Gastroenteritis MCQ
  • C. Food poisoning is a notifiable disease TRUE
  • A doctor who knows OR SUSPECTS the disease is
    obliged to notify the local Public Health
    department
  • D. Stool microscopy and culture is usually
    required FALSE
  • Unnecessary unless foreign travel, prolonged
    symptoms, severely ill, comes from an institution
    or is a food handler

15
Gastroenteritis - Dehydration
  • Mild (lt5)
  • Thirst, dry mouth, reduced urine output
  • Moderate (5-10)
  • Tachycardia, tachypnoea, sunken eyes, sunken
    fontanelle in babies
  • Severe (gt10)
  • Reduced skin turgor, drowsiness, irritability

16
Gastroenteritis - Dehydration
  • Rehydration formula
  • Correction of deficit
  • Degree of dehydration () X Weight (kg) X 10
    fluid loss in mls
  • e.g. A 5 dehydrated 20kg child has lost 1000mls.
    Goal is to replace this over 24 hours.
  • Maintenance requirements
  • 4ml/kg/hr for the first 10 kg.
  • 2ml/kg/hr for the next 10 kg.
  • 1ml/kg/hr for any weight over 20 kg.

17
Food poisoning - Incubation periods
  • Staph. aureus 1-6 hours
  • E coli 1-2 days
  • Shigella 1-3 days
  • Campylobacter 1-3 days
  • Rotavirus 1-7 days

18
Meningococcal MCQ
  • A. Up to 25 of adolescents carry Meningococcus
    as commensals
  • B. The peak incidence of meningococcal disease
    is in the 15-19 age group
  • C. The overall mortality of meningococcal
    disease is around 10
  • D. Serogroup B infections are commoner than
    Serogroup C infections

19
Meningococcal MCQ
  • A. Up to 25 of adolescents carry Meningococcus
    as commensals
  • TRUE
  • Carriage is in the nasopharynx. 10 of adults
    also carry the organism.
  • B. The peak incidence of meningococcal disease is
    in the 15-19 age group FALSE
  • Highest incidence is in children aged 1-5 with
    infants under 1 the next most commonly affected.
    Young people aged 15-19 is the next most affected
    group

20
Meningococcal MCQ
  • C. The overall mortality of meningococcal disease
    is around 10 TRUE
  • D. Serogroup B infections are commoner than
    Serogroup C infections TRUE
  • Type C was slightly less common than Type B but
    the introduction of the MenC vaccine in Nov 1999
    reduced Type C infection enormously

21
Meningococcus
  • Overall mortality remains around 10 in the UK
  • Case fatality ratios increase with age and are
    higher in individuals with serogroup C than with
    serogroup B infections
  • Mortality is higher in cases with septicaemia
    than in those with meningitis alone
  • In those who survive, approximately 25 may
    experience a reduced quality of life, with 1020
    developing permanent sequelae
  • The most common long-term effects are skin scars,
    limb amputation(s), hearing loss, seizures and
    brain damage

22
Meningococcus
  • Benzylpenicillin is the antibiotic of choice for
    the general practitioner before transfer to
    hospital, unless there is a history of immediate
    allergic reactions after previous penicillin
    administration.
  • The recommended dose is 1200mg for adults and
    children aged 10 years or over, 600mg for
    children aged one to nine years, and 300mg for
    those aged under one year.
  • Although benzylpenicillin may reduce the chance
    of isolating the causative organism, this is
    outweighed by the benefit to the patient, and new
    techniques are available that facilitate the
    diagnosis of meningococcal disease even after
    antibiotics have been given.

23
Meningococcus
  • Resuscitate!
  • Give antibiotics ASAP when clinically suspicious,
    particularly if there is a petechial or purpuric
    rash
  • In hospital
  • Cefotaxime 50mg/kg or 2g in adults
  • Ceftriaxone (80mg/kg)
  • Dexamethosone with / just before antibiotics
  • Adults 0.15mg/kg
  • Children 0.4mg/kg

24
Meningococcus
  • Household contacts are at increased risk of
    developing the disease.
  • Risk is highest in the first seven days following
    onset in the index case but persists for at least
    four weeks.
  • Immediate risk can be reduced by the
    administration of antibiotic prophylaxis to the
    whole contact group.

25
Meningococcus
  • Doctors, nurses, and paramedics who are directly
    exposed to nasopharyngeal secretions or pulmonary
    oedema from such patients, mainly during airway
    management (mouth to mouth resuscitation,
    intubation, and airway toilet), may be at some
    increased risk of meningococcal disease.
  • Current guidelines in the United Kingdom advise
    offering antibiotic chemoprophylaxis only to
    those undertaking mouth to mouth resuscitation.
  • In the United States chemoprophylaxis is
    recommended for healthcare workers who have had
    "intensive unprotected contact (without wearing a
    mask) with infected patients (eg intubating,
    resuscitating, or closely examining the
    oropharynx of patients)."

26
Meningococcus
  • Rifampicin
  • 600mg every 12 hours for two days in adults
  • 10mg/kg dose for children over one year
  • 5mg/kg for children less than one year
  • Ciprofloxacin as a single dose
  • 500mg is an alternative for adults
  • 250mg for children aged five to 12 years
  • not yet licensed in the UK

27
Meningococcus
  • Pregnant contacts
  • Rifampicin 600mg twice daily for two days
  • Intramuscular Ceftriaxone 250mg
  • Unless the index case received Ceftriaxone
    treatment in hospital, chemoprophylaxis should
    also be given to the patient before discharge.

28
Notifiable diseases MCQ
  • The following are notifiable diseases
  • A. Tuberculosis
  • B. HIV / AIDS
  • C. Influenza
  • D. Whooping Cough

29
Notifiable diseases MCQ
  • The following are notifiable diseases
  • A. Tuberculosis TRUE
  • B. HIV / AIDS FALSE
  • C. Influenza FALSE
  • D. Whooping Cough TRUE

30
Diseases notifiable (to Local Authority Proper
Officers) under thePublic Health (Infectious
Diseases) Regulations 1988
  • Acute encephalitis
  • Acute poliomyelitis
  • Anthrax
  • Cholera
  • Diphtheria
  • Dysentery
  • Food poisoning
  • Leptospirosis
  • Malaria
  • Measles
  • Meningitismeningococcalpneumococcalhaemophilus
    influenzaeviralother specifiedunspecified
  • Meningococcal septicaemia (without meningitis)
  • Mumps
  • Ophthalmia neonatorum
  • Paratyphoid fever
  • Plague
  • Rabies
  • Relapsing fever
  • Rubella
  • Scarlet fever
  • Smallpox
  • Tetanus
  • Tuberculosis
  • Typhoid fever
  • Typhus fever
  • Viral haemorrhagic fever
  • Viral hepatitisHepatitis AHepatitis BHepatitis
    Cother
  • Whooping cough
  • Yellow fever
  • Leprosy is also notifiable, but directly to the
    HPA, CfI, IMT Dept

31
DoH Green Book
  • Comprehensive
  • Many notifiable diseases
  • Regularly updated
  • Includes clinical information
  • Immunisation against infectious disease
  • Edited by
  • Dr David Salisbury CB FRCP FRCPCH FFPHM
  • Director of Immunisation
  • Department of Health
  • Dr Mary Ramsay BSc MB BS MRCP MSc MFPHM FFPHM
  • Consultant Epidemiologist
  • Health Protection Agency
  • Dr Karen Noakes BSc PhD
  • Principal Scientist
  • Immunisation
  • Department of Health
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